In recent years, along with the development of various electronic products, multimedia systems such as home theater systems have become more and more popular. In multimedia systems, other than screens, sound systems are the most important hardware components. Relative to mono sound systems, stereo sound systems provide presence sound effects with a plurality of speakers disposed in symmetry playing audio signals of different sound channels, respectively.
The most common stereo sound system is a binaural sound system comprising a left channel and a right channel. It is very important to keep a left channel signal and a right channel signal in the same phase, during recording or post-processing music files (e.g., during sound mixing, encoding, and decoding procedures). If, for instance, the left channel signal and the right channel signal have a 180° phase difference, playing a pleasing replication of the sound can be problematic.
In addition, in a sound system employing AGC (auto gain control) for adjusting volume, a half of a sum of the left channel signal and right channel signal is generally regarded as a basis for determining amplitude of an audio signal. That is to say, if the phase of the left channel signal differs from that of the right channel signal, a corresponding detection result of amplitude will become extremely small. In such circumstances, speakers with an AGC mechanism are likely to play at an increased volume, and thereby disrupt the hearing of listeners.